Power bender



April 25, 1939.

C. P. CHAMBERLIN ET AL POWER BENDER Filed Sept. *29, 1957 2 Sheets-Sheet l INVENT0R5. (Zara/n1: F (id/722671257,

Patented Apr. 25, 1939 UNITED STATES PATENT OFFICE POWER BENDER Application September 29, 1937, Serial No. 166,386

2 Claims.

This invention relates to apparatus for bend ing metal and particularly to apparatus that is adapted to bend strips of sheet metal of various cross-sectional configurations into a predetermined shape.

Objects of the invention include the provision of apparatus for bending strips of sheet metal of non-planular cross-sectional configuration into predetermined shape without causing a buckling of the metal; to provide mechanism by means of which flanged sheet metal strips may be bent into predetermined shapes; to provide apparatus of the type described including a rotatable die member having a peripheral contour corresponding with the shape of the desired finished article and peripherally shaped to accommodate the cross-sectional configuration of the strips desired to be bent, together with means for yieldably clamping the strips against the peripheral surface of the member while the member is rotating whereby to cause the strips to assume the form of the peripheral surface of the member and yet maintain the strip against deformation from its intended cross-sectional configuration; to provide apparatus of the type described in which those portions of the strip being formed and lying in a. plane radial to the direction of rotation of the member are yieldably maintained between radially directed surfaces preventing deformation of the cross-sectional configuration of the strip from its intended form; the provision of an apparatus of the type described in which rigid means having a surface conforming at least in part to the cross-sectional configuration of the strip to be formed is yieldingly pressed against the surface of the strip so as to maintain it in a radial di-. rection against the periphery of the rotatable member whereby to cause it to conform to the peripheral shape of the rotatable member; the provision of an apparatus as above described in 'which the radially yieldable pressure member is so constructed and arranged as to advance and retract with respect to the axis of rotation of the rotatable member where such peripheral surface is of eccentric relation with respect to the axis of rotation of the rotatable member, or in which the distance from the axis of rotation of the rotatable member to various portions of its peripheral surface vary around the periphery; the provision of a construction as last described in which the radially yieldable member exerts a constant pressure against the strip to be formed to maintain it against the periphery of the rotatable member; to provide apparatus of the type described including fluid actuated pressure exerting parts adapted to yieldingly maintain the strips being acted upon in proper cooperation with respect to the periphery of the rotatable member; and in general to provide an apparatus of the type described that is simple in construction, economical to manufacture, and emclent in use.

The above being among the objects of the present invention the same consists in certain novel features of construction and combinations of parts to be hereinafter described with reference to the acompanying drawings, and then claimed, having the above and other objects in view.

In the accompanying drawings which illustrate a suitable embodiment of the present invention and in which like numerals refer to like parts throughout the several different views,

Figure l is a partially broken, vertical sectional view taken centrally through a power bending machine;

Fig. 2 is a reduced top plan view of the machine shown in Fig. 1;

Fig. 3 is a horizontal sectional view taken on the line 33 of Fig. 1;

Fig. 41s aside elevational view of a completed article such as produced by the machine illustrated in the previous views; and,

Fig. 5 is an enlarged transverse sectional view taken on the line 55 of Fig. 4 illustrating the cross-sectional configuration of the particular article illustrated as being produced on the machine shown in the previous views.

While the present invention is applicable for use in the bending of metal strips of any crosssectional configuration to a predetermined completed shape, it is particularly adapted for the bending of non-planular sheet metal strips. By non-planular sheet metal strips is meant particularly sheet metal strips provided with flanges, beads, grooves or other portions offset from the plane of the main body portion thereof. As is well recognized in the art the problem of bending the strips of such cross-sectional configuration offers a considerable problem in that in bending such strips out of a straight form those portions of the strip extending out or away from the plane of the main portion of the strip have a tendency to distort out of their desired .position with respect to the main body portion and to become wrinkled or otherwise displaced from their proper and desired relationship with respect to the main body portion. Particularly where all or most of one surface of the strip is curved or of irregular shape are formed from strips of metal having a cross-sectional conflgu ration as above generally described, the garnish moldings employed in the bodies of automobiles around the window openings and in other loca- 'tions are a good example of articles of the type under discussion and, accordingly, for the purpose of illustration only the form of the apparatus shown in the accompanying drawings has been designed to form a garnish molding for a rear quarter window of an automobile body, the particular shape and section of which is illustrated in Figs. 4 and 5, respectively.

Referring to Figs. 4 and 5 and particularly to Fig. 4, it will be noted that the garnish molding there indicated generally at 16 includes two sides l2 and i4 which are straight for the greater portion of their length and are joined together in perpendicular relationship to each other by a portion i6 of relatively sharp curvature. The remaining end portions of the sides 12 and i4 are curved as. at i8 and 28, respectively, and are joined to opposite end portions of a curved portion 22 of relatively generous curvature, the

whole forming a closed loop. It will be understood by those skilled in the art that the garnish molding I 8 is arranged on the inner side of a window opening in an automobile and that the inner face thereof overlies the margins of the interior flnish (not shown) surrounding the window opening to which the garnish molding I8 is to'be adapted. While, as previously explained, such garnish molding may have different cros-sectional configurations, all of them are usually made from sheet metal and usually include one or more flanged edge portions directed at an angle to the plane of the main body portion of the molding, and/or beaded or other similarly offset portions. As a matter of illustration it is assumed that the garnish molding i8 is of a cross-sectional configuration such as shown in Fig. 5 and in which it will be noted that it includes the main body portion 24 of generally planular conformation having oppositely directed flanges 26 and 28 at opposite marginal edges thereof. The main body portion 24 is also provided with a bead 38 on one face thereof extending in parallelism to the flange 26 and slightly spaced therefrom and which head 38, due to its method of formation as by rolls or other conventional means, forms a complementary groove 32 in the opposite face of the main body portion 24. It will .be readily apparent that any attempt to bend a strip of metal of the crosssectional configuration illustrated in Fig. 5 about a line parallel to the plane of the main body portion 24 and perpendicular to the plane of the flanges 26 tnd 28 would necessitate the stretching of the metal in one of the flanges 26 or 28 and compression of the metal in the other thereof, the latter flange in particular having a tend-.

ency to ripple or wrinkle during such operation, the bead 38 having a tendency to flatten out, and the metal of the main body portion 24 adjacent each of the flanges -26 and 28 having a tendency to distort out of its true and desired form. By the use of the apparatus constituting the present invention such bending of a member having a cross-sectional configuration such as that shown in Fig. 5 may be accomplished without distorting or otherwise affecting the crosssectional configuration of the strip, resulting in a final product that is smooth, devoid of defects, and of a character capable of enhancing the appearance of the automobile to which it is applied.

Referring to the drawings and particularly to Fig. 1 it will be noted that the apparatus comprising the present invention includes a suitable table 38 of rigid construction provided with suitable legs or supports 32 by means of which it may be suitably supported from a floor or the like. Adjacent one end of the table and rotatably supported by suitable bearings 34 therein in a vertical hollow shaft 36 which projects both above and below the table 38. The table 38 immediately surrounding the shaft 36 is thickened on its lower surface as at 38 and secured to the lower face of the thickened portion 38 as by screws 48 is a spider 42 which carries centrally thereof an, additional bearing 44 for the shaft 36. Secured to the lower face of the spider 42 by the same screws 48 that secure the spider 42 to the table38 is a drum-like housing 46 having its closed lower end apertured for passage of the shaft 36 therethrough and provided with an additional bearing 48 therefor. The bearings 34, 44 and 48 cooperate to prevent axial movement of the shaft 36 with respect to the table. Within the housing 46 a worm wheel 58 is non-rotatably secured to the shaft 36.

As best illustrated in Fig. 3 a. horizontally extending shaft 52 is projected through a side of the housing 46 and is rotatably supported therein by means of suitable bearings 54. Within the housing 46 the shaft 52 is provided with a worm 56 which lies in meshing relationship with respect to the worm wheel 58. One projecting end of the shaft 52 is provided with a pulley 58 for the purpose of permitting the shaft to be driven thereby. An electric motor 68 is suitably supported from one of the supports 32 through a hinged connection 62 as indicated in Fig. 3 and its drive shaft 64 is provided with a pulley 66 aligned with the pulley 58 and drivingly connected thereto by means of a plurality of belts 68. It will thus be understood that rotation of the motor shaft 64 will cause a corre sponding rotation of the shaft 52, worm 56, worm wheel 58 and. shaft 36. The hinged connection 62 will be recognized as a standard form of motor mounting arranged to permit the weight of the motor 68 to maintain the belts 68 in taut condition.

It will be noted from an inspection of Fig. 3 that the shaft 52 is provided with a conventional form of solenoid brake indicated generally at 18 arranged to be freed when its solenoid I2 is energized simultaneously with the motor 68 and adapted to set the brake through the spring 14 when the motor 68 is de-energized, thus permitting the shaft 36 to be brought to a condition of rest quickly upon opening the circuit to the motor 68.

Suitable means such as the passages 16, 18 and 88 formed in the table 38 and its extension 38 are provided for the introduction of lubricant to the bearings 34 and 44. The housing 46 is adapted to maintain a supply of lubricant in its lower portion for lubrication of the worm wheel 58 and worm 56 as well as for the bearings 48. Lubricant is prevented from escaping downwardly between the shaft 36 and the housing 46 by means of suitable seals 82 provided around the shaft 36 in the lower end of the housing 46.

.wardly therefrom through. the hollow interior of the shaft 36 in which it is slidably received. The lower end of the cylinder 84 is provided with an axial projection 90 on which is rotatably mounted a pair of hollow slip rings 82 and 94, respectively. A passage 86 connects the interior of the slip ring 92 with the interior of the cylinder 84 below the piston 86 and a series of passages 98 connect the hollow interior of the slip ring 94 with the interior of the cylinder 84 above the piston 86. Pipes I00 and I02 connect the interior of the slip rings 92 and 94. respectively, with a conventional form of control valve mechanism indicated generally at I04 and by means of which air may be introduced into and/or exhausted from the opposite sides of the piston 86 in order to effect its reciprocation in the cylinder 84. i

A head H0 is relatively non-rotatably secured to the shaft 36 immediately above the table 30 and fixed to the upper face of the head I I0 is a forming die H2 in the present instance shown as of ring-like or loop-like formation. It will be understood that the peripheral shape of the forming die H2 as viewed in plan view substantially corresponds to the shape of the desired finished article. Accordingly, it will be understood that in the case of the particular article which it is here assumed the apparatus is designed to form the plan view of the-forming die H2 will correspond to the shape of the garnish molding shown in Fig. 4 with the following difference only. Inasmuch as one end of the strip which forms the garnish molding I0 shown in Fig. 4 is provided with a tongue I20 adapted to be received in a corresponding slot formed in the opposite end of the strip so as to hold these free ends against displacement in service, the tongue will overlap the opposite end of the strip during the formation of the molding and, accordingly, in such case the peripheral surface of the forming die I I2 corresponding with the straight end portion of the garnish molding carrying the tongue I20 is somewhat inclined in wardly as is illustrated at I 22 in Fig. 2 so that the free ends of the strip will be offset from one another when initially formed. It will be understood that the molding I0 is of sufficient resiliency to permit the tongue I20 to be sprung into its corresponding groove in the opposed free end of the moulding after it has been bent to the shape shown. The outer peripheral edge face of the forming die H2 is shaped in a manner complementary to one face of the garnish molding I0, in the particular instance shown, to the lefthand face as viewed in Fig. 5 and so that when the molding is applied thereto the fiange 26 will overlie the upper marginal face of the die H2 as illustrated best in Fig. l.

A head I30 of approximately the same peripheral shape as the die H2 is non-rotatably secured to the piston rod 88 above the die H2 as best shown in Fig. l. A clamping ring I32 of approximately the same size and shape as the die H2 is fixed to the lower face of the head I30 in complementary relationship with respect to the die H2. A pair of pins I34 arranged in axially parallel relation with respect to the piston rod 88 and shaft 36 are fixed in the head I30 and project downwardly therefrom and are slidably received in complementary openings formed therefor in the head H0 so as to cause equal rotation of the die H2 and pressure ring I32 at all timeswithout restricting relative axial movement between them.

As best illustrated in Figs. 1 and 2 the upper face of the table 30 is provided with a troughlike depression I40 formed therein and disposed in a radial relation with respect to the shaft 36 and in the bottom. of this depression I40 a pair of spaced ways I42 are formed. A head I44 is slidably received upon the ways I42 for reciprocable movement in a direction radially of the shaft 36. The head I44 has fixed therein a pair, of vertically spaced forwardly projecting pins I46 and I48 upon the forwardly projecting ends of which is supported a second head I50 arranged for pivotal movement around the vertically directed pin I52 provided for securing-the head I50 to the projecting ends of the pins I46 and I48. If desired a coiled spring such as I54 may be maintained under tension between the pin I52 and a second pin I56 secured to the head I44 so as to set up suflicient friction in the pivotal connection between the heads I44 and I50 to prevent entirely free pivotal movement of the head I50, as well as to take up any play between these parts. The upper forward edge of the head I50 has fixed thereto a die member I60 in the form of a bar, the forward face of which is formed to a shape complementary to the righthand face of the garnish molding I 0 as viewed in Fig. 5.

The heads I44 and I 50 are reciprocable relative to the ways I42 by means of a piston I64 working in a cylinder I66 located at the righthand side of the machine as viewed in Figs. 1 and 2. The sylinder I66 is supported by being secured to a bracket I68 secured to the righthand edge of the table 30 as viewed in Figs. 1 and 2 and is positioned co-axially of the pin I48 and parallel with the ways I42. The piston I64 is provided with a piston rod I10 which projects out the lefthand end of the piston I66 and through the bracket I68 and is received within a sleeve coupling I12 in which the righthand end of the pin I48 is also received. The adjacent ends of the pins I48 and of the piston rod I10 are secured to the sleeve I12 by means of pins I14, the connection being such as to preferably permit a slight amount of universal movement between the pin I48 and the piston rod I10. The axial position of the piston I64 and the cylinder I66 is controlled by means of air introduced into and exhausted from opposite ends of the cylinder I66 through pipes I16 leading to the same air control valve I04 that controls the cylinder 84 previously described. A pair of control buttons I18 positioned on the top of the bracket I 68 are suitably connected with the valve I04 in a conventional manner so that one of the buttons I18 controls the operation of the piston 86 and the (uglier thereof controls operation of the piston A control button I80 also located on the top of the bracket I68 is provided for starting the motor 60 and although it may also be employed for stopping the motor 60 it is preferable to have some automatic means for stopping the motor 60 and consequently the rotating head I I0 including the forming die H2 at a predetermined point in their rotation upon completion of each cycle of operation. Accordingly, in order to efiect this last result a cam member I82, shown in Fig. 1, is secured to a side of the cylinder 84 and a cut-out switch I84 suitably connected to both the motor 60 and the control button I is secured in fixed relation with respect to the housing 46 by means of elongated brackets I86. The cut-out switch I84 is provided with an operating member I88 disposed in thepath of travel of the cam I82 so that each time the cylinder 84 makes one revolution the cam I82 will strike the operating mem ber I88 and open the circuit to the motor 60, it being understood that such circuit may be manually closed by operation of the button I80. It will, of course, be also understood that the cam I82 and cut-out switch I84 are so arranged with respect to the position of rotation of the forming die II2 that the machine will come to rest with the forming die in a loading position.

In the operation of the above machine the stock to be acted upon to form the garnish molding I0 will be received at the machine as a straight strip of material of the cross-sectional configuration illustrated in Fig. 5 and it is the function of the machine to form such strip of material into the shape illustrated in Fig. 4. It will also be understood that the view illustrated in Fig. 2 shows the machine after the forming die II2 has traveled through approximately 90 of movement during a forming operation and that in actual practice the straight but inclined portion I22 will be facing and opposed to the operative face of the die member I60. With the machine in the last mentioned position the operatorv will have operated the control buttons I18 so as to withdraw the heads I44 and I50 to the right as viewed in Figs. 1 and 2 preferably to the extent of their movement and so as to raise the piston 86, head I30 and pressure ring I32 to their fullest extent. The operator will then insert a straight strip of stock between the die I60 and forming die H2 in such a manner that the one face of the strip will lie in complementary relation with respect to the peripheral forming face of the die II2. In the case of the particular die II2 shown the strip will be inserted to such an extent that its tongued end will substantially abut against the radially directed shoulder at the inner end of the inclined portion I22 of its periphery and in which position the tongue I20 may be slipped over a pin I90 secured in the peripheral face of the die H2 and which tongue I20 is apertured to receive it. The pin I80 thus acts as a locating stop for the strip of stock as Well as serves to hold this end of the strip of stock against pulling away from or mov ing relative to the die I I2 during the forming operation. The operator then operates the proper button I18 to move the heads I44 and I50 to the left as viewed in Figs. 1 and 2 and so that the die member I60 will contact the corresponding face of the strip in complementary relation with respect thereto and press it firmly against the peripheral face of the forming die II2. At the same time or immediately thereafter he will operate the other button I18 so as to move the piston 86 downwardly in the cylinder 84, thus drawing the pressure ring I32 downwardly against the upper flange 26 of the strip and yieldingly but firmly clamp it down against the upper face of the forming die H2. The button I80 is then operated to start the motor 60 which immediately starts rotation of the forming die H2 and as it rotates it carries the strip around with it, and as it rotates the die member I60 yieldingly presses the strip against the periphery of the forming die H2 and causes it to assume a shape corresponding to the shape of the periphery of the die II2.

It will be observed that because of the varying radial distances of various portions of the periphery of the die II2 with respect to the axis of the shaft 36 it will be necessary for the heads- I44 and I50 with the die member I60 to advance toward and recede from the axis of the shaft 36 during rotation of the die II 2 and in the present case this is taken care of by the die II2 forcing these parts back against the pressure of the air in the cylinder I66 by a camming action during certain phases of rotation and by the pressure of the air in the cylinder I66 causing these parts to move inwardly to maintain their operative relation with respect to the periphery of the die II 2 during other phases of operation. Thus it will be noted that although this apparatus permits the die member I60 to move inwardly and outwardly to accommodate the irregularities in the radial distances of various portions of the die I I2 from its axis of rotation, nevertheless the die member I60 is constantly pressed against the periphery of the die member I I2 with a constant force during every phase of rotation of the die member II 2 during the forming process. The piston 86 holds the pressure ring I32 downwardly so as to clamp the flange 26 between it and the top face of the die I I2 during the forming operation and thereby prevents it from wrinkling or otherwise deviating from its true and intended form. Likewise the flange 28 is held between the cooperating faces of the die members H2 and I60 and is likewise maintained against distortion. Due to the fact that the cooperating faces of the die member H2 and the die member I60 are complementary to the opposite faces of the strip being acted upon at the moment such strip is being bent and the flanges at the opposite edges of the strip are held against distortion from their intended form, it is impossible for the metal of the strip during the bending operation to distort out of its true and intended form and consequently the cross-sectional configuration of the molding I0 in final form will be identical to its cross-sectional configuration in the straight strip of stock from which it is formed. For this reason distortion of the metal of the strip is effectively prevented and no wrinkles or other blemishes of the strip appear in the finished product. It will also be understood that the strip of stock which is initially fed into the device is of exactly the correct length required in the finished product and that when the machine has made a complete revolution so as to entirely complete the forming of the shape of the molding the cam I82 will cause actuation of the cut-out switch I84 and the machine will come to rest, whereupon the operator may operate the buttons I18 to withdraw the pistons 86 and I64 upon which the finished molding may be lifted off of the die II2, the tongue I20 inserted in its cooperating slot in the opposed free end of the strip, and the article thus completed except for applying a suitable finishing coating of paint or the like where necessary or desirable.

Formal changes may be made in the specific embodiment of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

What we claim is:

1. In apparatus for bending a straight strip of metal stock, having a main body portion and a flanged edge portion, into a predetermined shape of non-circular outline including, in combination, a die member having a peripheral face of non-circular conformation corresponding approximately to the conformation desired in the final product, means for rotating said die memher, the peripheral face of said die member being shaped in cross-section complementary to the cross-sectional configuration of one face of said strip, a portion of said die member adjacent the periphery being substantially straight and at an angle to the peripheral face, yieldable means movable axially with respect to said die member having a portion substantially parallel to said last-named portion operable to yieldably clamp the flange of said strip between it and said portion of said die member, a head movable in an approximately radial direction with respect to the axis of rotation of said die member, a second die member carried by said head and provided with a face the cross-sectional configuration of which is complementary to that face of said strip which is not adapted to engage the peripheral face of the first mentioned die-member, and means yieldable under the camming action between said die members constantly urging said second die member towards said first die member during operative periods of said apparatus.

2. Apparatus 0f the type described including, in combination, a hollow shaft, means for rotating said shaft, a head fixed to said shaft for rotation therewith, a die member fixed to said head for rotation therewith, a rod slidable in said shaft, a clamping head secured to said rod beyond that end of said shaft supporting said die member, a piston secured to said rod at the opposite end of said shaft, a cylinder fixed to said shaft for rotation therewith and cooperating with said piston, means for introducing and exhausing fluid from opposite sides of said piston during rotation of said cylinder, a head mounted for slidable movement in a direction approximately radial with respect to said shaft, a second die member carried by said head in cooperative relation with respect to the periphery of the first mentioned die member, a piston connected with said head, a cylinder receiving said piston, and means for introducing and exhausting fluid from opposite sides of the last mentioned piston whereby to cause said head to be advanced toward or retracted from the first mentioned die member, said piston being yieldable in said cylinder under a camming action between said die members whereby said head may advance and retract with respect to the first mentioned die member while being constantly urged toward said first mentioned die member.

CLARENCE PICHAMIBERLIN. JOHN H. TONER. 

